In the fabrication of articles such as cables, pipes, footwear, foams and the like, the polymeric compositions from which these articles are made must often be melt blended. The compositions often comprise silane-functionalized resins and a catalyst, and these resins undergo crosslinking through their silane functionalities upon exposure to moisture at either ambient or an elevated temperature. One key requirement in this process is to minimize scorch, i.e., premature crosslinking, of the resin during the melt processing, e.g., extrusion, molding, etc. The minimization of scorch is typically achieved by using “dry” compositions during melt processing at temperatures above the melting point of the resin (e.g., above 200° C. in the case of polyethylene), and the addition of scorch retardants, e.g., a monomeric silane, etc.
Another important consideration in the fabrication of these articles is to achieve crosslinking within a short period of time, e.g., hours, days, after the melt processing is completed. This is achieved by curing at elevated temperatures, e.g., in excess of 70° C., and/or through the use of powerful catalysts such as sulfonic acids. As the thickness of the fabricated article increases, so does the time that moisture takes to diffuse into and through the polymer composition, even at elevated temperatures. This adds to the cost of the fabrication process. As such, the polymer fabrication industry has a continuing interest in accelerating the moisture-cure of silane-functionalized resins beyond that achievable with strong acids, and preferably with an acceptably low level of scorch.